Transcontinental Interstate 10 serves the southern tier of the United States between Southern California and the Desert Southwest and the Southeastern United States. Known as the Christopher Columbus Transcontinental Highway, I-10 is one of three coast-to-coast Interstates, the others being I-80 and I-90.
Within California, Interstate 10 originates in Santa Monica just off the Pacific Ocean. A heavily traveled freeway, I-10 advances east across Los Angeles where it briefly combines with Interstate 5. Following the San Bernardino Freeway from I-5, I-10 continues to the Inland Empire, leaving the greater Los Angeles metropolitan area some 70 miles east of Downtown Los Angeles. I-10 enters the desert just beyond the narrow San Gorgonio Pass. Beyond there, the freeway becomes characteristic of a rural desert, one it will retain through much of its course through the west. Desert cities in California include Palm Springs, Indio and Blythe.
Phoenix is the next major city, which is growing at an amazing rate through central Arizona. Interstate 10 forms a freeway loop with I-17 through Downtown Phoenix before making a southeasterly turn across the Sacaton Mountains and Santa Cruz Flats toward Tuscon. I-10 runs west of the Tuscon business district, representing one of just two freeways serving the metropolitan area. The freeway navigates along a gradual arc southeast from the city to San Pedro Valley at Benson and then northeast across Sulphur Springs Valley toward Bowie.
Heading east across the Peloncillo Mountains, Interstate 10 enters New Mexico. This stretch is prone to high winds and during periods of dust storms the freeway may be shut down with traffic detoured north of the Animas Valley via U.S. 70 from Lordsburg. I-10 overlays U.S. 70 and historic U.S. 80 east across open desert to Deming to the Mesilla Valley and Las Cruces.
Skirting the Mexican Border and the Rio Grande near El Paso, Interstate 10 crosses the vast expanse of West Texas. The freeway has several at-grade ranch access points between The El Paso County line and Van Horn, due to the remote character of the highway and the extremely low traffic volumes of the region. Those same aspects allow for it to be posted with an 80 mile per hour speed limit.
Traveling east from Van Horn, I-10 traverses northern reaches of the Davis Mountains, splitting with Interstate 20 in a sparsely populated area east of Fort Kent. Elevation changes mark the next several hundred miles, as I-10 progresses east to small cities such as Junction and Kerrville. When approaching San Antonio from the northwest, I-10 transitions to a suburban freeway from Boerne into the Alamo City.
Comprising a heavily traveled commuter route, Interstate 10 forms part of a loop encircling Downtown San Antonio with I-35 to the west and U.S. 90 to the south. The freeway overlaps with or parallels U.S. 90 for the remainder of the route east to Houston. Suburban frontage reappears along I-10 at Katy, with the freeway swelling to 16 lanes along the Katy Freeway through the western Houston suburbs. The Baytown East Freeway continues I-10 toward industrial areas at Channelview and Bayport. The freeway eventually exits the Lone Star State at Orange, east of Beaumont.
Entering southern Louisiana, Interstate 10 stays in land through areas of timberland, agricultural areas, and bayous. The freeway joins the urban centers of Lake Charles, Lafayette and Baton Route. Several major sections of the highway are elevated in the Pelican State, including the Acadian Thruway leading toward Baton Rouge and along the periphery of Lake Pontchartrain. I-10 splits with I-12 to loop southward into Greater New Orleans while I-12 provides a bypass for long distance travelers east into coastal Mississippi.
I-10 and I-12 reconvene at Slidell, just west of the Pearl River and Mississippi state line. Interstate 10 crosses the Mississippi Gulf Coast through northern reaches of Gulfport, Biloxi and Moss Point. Combined with commuter traffic and long distance freight, a substantial section of Interstate 10 in the Magnolia State was expanded to six lanes.
Turning northeast toward the Port City of Mobile, I-10 circumvents Mobile Bay through the George Wallace Tunnel at Downtown, and across the four lane Mobile Bayway to Spanish Fort and Daphne. The freeway becomes rural again east of Loxley, traversing areas of pine forest into the Sunshine State outside Pensacola.
Once in Florida, Interstate 10 travels across the Pensacola area before turning more inland from the coastal estuary of Escambia Bay. The freeway runs along the northern boundaries of Elgin Air Force Base along a lightly traveled stretch to Crestview and Defuniak Springs. Crossing the Apalachicola River, I-10 enters Eastern Time Zone and proceeds east toward the capital city of Tallahassee.
Interstate 10 stays through rural areas of Northern Florida, meeting I-75 outside Lake City and crossing a wide swath of Osceola National Forest toward Jacksonville. Continuing into Jacksonville, Florida’s largest city, I-10 expands into a six and eight lane urban freeway, concluding at I-95 between Downtown and the Fuller Warren Bridge spanning the St. Johns River.
Mobile River Bridge
Within the state of Alabama, Interstate 10 will eventually be relocated onto a new alignment and bridge over the Mobile River. Associated work will rebuild the Mobile Bayway from twin two lane bridges to an eight lane viaduct system. A Draft Environmental Impact Statement was released on July 22, 2014 for the new bridge and Bayway widening.
First envisioned in the 1990s, the proposed 2,300-foot-long bridge was estimated to cost $350 million, with funding primarily from federal dollars. A spokesman for U.S. Rep. Jo Bonner R-Mobile indicated in 2003 that local officials have to agree to support the plan first, but that support was not concrete. However then-Mayor Mike Dow of the city of Mobile gave the project his full support. Mobile County Commission President Freeman Jockisch concurred with that, adding that Mobile area leaders were united in their support for the project. 2003 state traffic studies concluded that the Wallace Tunnel was reaching capacity and that the adjacent Bayway, the seven mile twin viaduct over Mobile Bay, was in need of expansion. The average daily traffic for the Wallace Tunnel in 2002 was 59,898 vpd. The tunnel was designed to handle 36,000 vpd.1,15
A unique bridge design was sought for the span, with “V” shaped towers built on single piers. Ron Poiroux, then-division engineer at the Alabama DOT District 9 Mobile Office, indicated that it was up to the U.S. Congress to approve the $200 million bridge and $150 million Bayway expansion. A $650,000 feasibility study was previously completed in 1997. The project was slated to take about eight years to complete, with a potential completion date by 2012.1 As of 2012, no bridge plan was agreed upon by city or DOT officials and the tunnel and Bayway remained with four overall lanes.
The new span gained traction in 2013, with more public support and potential funding, leading to the DEIS issued in July 2014. The 2014 estimate for building the Mobile River bridge and expand the Bayway is $850 million.15
If the Environmental Impact Statement is finalized with funding secured and rights of way purchased, construction will take six to eight years to complete. The cable stayed span will provide a vertical clearance of 215 feet.15 All electronic tolling will be implemented both on the new bridge and the George Wallace Tunnel to cover the costs. The tunnel will remain open, serving local traffic to Downtown Mobile, and be designated as Business Loop I-10.
The section of Interstate 10 through Southern California is part of High Priority Corridor 34: Alameda Corridor East and Southwest Passage. East in Arizona, Interstate 10 between Phoenix and Tucson is part of High Priority Corridor 26: CANAMEX Corridor.
The completion of Interstate 10 in the Southwestern States resulted in the demise of several parallel U.S. Highways, including U.S. 60, 70, 80 and 290. Both truncated, U.S. 60 and 70 followed I-10 from Los Angeles to Phoenix. U.S. 60 ends at I-10 east of Quartzsite, Arizona, and U.S. 70 ends at U.S. 60 in Globe, Arizona. U.S. 80 was replaced by several Interstates in the west; I-10 replaced U.S. 80 between Phoenix and the I-10/20 split near Kent, Texas. Prior to 1992, U.S. 290 also followed the I-10 corridor from I-20 to the Kimble County, Texas. East of San Antonio, I-10 closely parallels, but for the most part does not replace, U.S. 90 all the way to Jacksonville.
Within the Golden State, Interstate 10 is a major through traffic corridor, connecting Southern California with the growing Inland Empire and desert cities such as Palm Springs, Indio and Phoenix, Arizona. As such, the freeway is often as busy as Interstate 5 in the Central Valley, carrying weekend travelers across the vast desert. In the Los Angeles Basin and Inland Empire, relief to perennial traffic was sought with the construction of Interstate 210, the Foothill Freeway, between Redlands and San Dimas. Completed July 24, 2007, the freeway remains signed as California State Route 210.
For a complete history of I-10 construction in Arizona, visit the Interstate 10 Arizona guide on AARoads. The final segment of the route in Arizona built was the Papago Freeway in Downtown Phoenix, which opened on August 10, 1990. This included the Deck Park Tunnel north of Downtown and represented the final section of the transcontinental route completed.10 Original plans called for an elevated Interstate 10 freeway through Downtown Phoenix in 1960, but the ultimate facility built travels mostly below grade.
A $12.2 million widening project along Interstate 10 in West Phoenix got underway in Fall 2003. The widening resulted in the expansion of I-10 from six to eight lanes between 59th Avenue (Exit 134) and 91st Avenue (Exit 139). An additional westbound lane, along with new auxiliary lanes , opened to traffic on November 9, 2003. An new eastbound through lane and auxiliary roadways were open to traffic in December 2003.6 These projects were two of many taken to provide additional traffic relief in Phoenix, fueled by major expansion of the metropolitan area with new developments in formerly virgin desert.
Long-range plans for I-10 within Maricopa County in the mid 2000s suggested additional expansion and a parallel freeway (SR 30 / I-10 Reliever) to be constructed southward Plans for Loop 202, the southern and eastern belt route for the Phoenix area, advanced with freeway construction south from I-10 underway through 2020.
Within Texas, Interstate 10 was an original Interstate Highway, and it was approved by the Bureau of Public Roads in 1959 and by the Texas State Highway Commission in 1962 with 879 miles.9 Sections of I-10 were under construction in the Lone Star State between 1959 and 1982. Early emphasis was on completing the freeway through and between San Antonio and Houston; this was mostly done by 1968 and completely by 1972. In West Texas, much of the construction occurred in the 1960s and 1970s. The El Paso and Van Horn bypasses were built first; the last section to open was the Fort Stockton bypass.
The significant reduction in traffic between El Paso and San Antonio is the least populated stretch of Interstate 10. Due to low traffic counts and long sight lines through remote West Texas, transportation officials approved an increase in the speed limit for 432 miles of IH 10 between El Paso and Kerrville to 80 miles per hour in 2006.11
Through central San Antonio, I-10 was built on two decks to maximize utility of space in a tight right of way. Leading into Houston, the 2002-08 Katy Freeway reconstruction rebuilt all of I-10 from Katy into Houston with additional lanes, ramp realignments, and the Katy Tollway.
Storm surge from the August 29, 2005 landfall of Hurricane Katrina toppled or misaligned many of the 309 ton concrete segments of the 1965-built twin spans of Interstate 10 across Lake Pontchartrain in southeastern Louisiana. The bridges were closed and an emergency contract of $30.9-million13 was awarded to reopen the crossing. This occurred October 14, 2005 with the opening of the eastbound bridge with two-way traffic. The westbound bridge was restored with one lane of traffic on January 5, 2006.